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Cold vs Hot Runner Molds – Benefits to Both

by Administrator29. June 2016 17:58

Following part design and material selection the next step in plastic injection molding is getting the tool designed and made. One of the earliest decisions to make is whether to have a cold runner or hot runner system. 

Cold Runner

When a mold is designed for a cold runner system, you have a channel formed between the two halves of a mold, allowing the plastic to move from the injection molding machine nozzle to the cavities. When the mold opens to eject the newly formed parts, the material in the runner system is also ejected, resulting in scrap material.

Hot Runner

This system is an assembly of heated components that inject molten plastic into the cavities of the mold. A hot runner system typically includes a heated manifold and a number of heated nozzles. When a mold with a hot runner system opens, only the part ejects as material in the runner system is kept molten and will fill into the part cavity during the next cycle.

So which do you choose?

Benefits of a Hot Runner System:

  • Eliminate the runner thus eliminating expensive scrap (and potential regrind issues) and you have less handling of materials. 
  • Lower the cycle time since you are not waiting for the cold runner to cool during the cycle. Removing the runner also improves the injection screw recovery and injection time since due to the smaller shot size
  • Design flexibility because you can locate the gate at many points on the part

 Downsides of a Hot Runner System:

  •      Very expensive to design and build
  •      Maintenance of the mold requires higher level of expertise
  •      Complicated design 

Benefits of a Cold Runner System:

  • Less expensive to manufacture
  • Lower maintenance costs
  • Easier to use for a wide variety of polymers

Downsides of a Cold Runner System:

  • Scrap waste through runner system and handling of materials
  • Potentially incorporating regrind into the system

When you are making the decision to choose between the a cold or hot runner system it is important to have a thorough understanding of your part, the material, and the estimated annual units. While hot runner systems are expensive to make, the scrap material waste and extended cycle time can offset the tooling savings.

 

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Injection Molding | Manufacturing | Plastics | Training

An Insider's View - American Injection Molding Institute (AIM) Certificate Program

by Administrator28. March 2016 14:03

My name is William Allen. I have been around plastics injection molding my entire life. My parents actually met while working in an injection molding facility as young adults and I can remember recognizing the sounds and smells of a plastics plant as early as five years old. When I found myself on the hunt for a job in 2005 I made my way into the plastics world as well. Starting out as an operator I was able to see plastics manufacturing from many angles as I worked my way up through the ranks. My first formal training in the realm of processing came in the form of a two day class and a one month crash course from a newly hired engineer on staff at Nampac (North American Packaging) which, at the time, was located in East Cleveland Ohio. That was in 2007. At the time, I was strictly working with polypropylene making one product – buckets - in several sizes and colors on the 11 presses we had in house. It wasn’t until midway through 2008, when Nampac closed its doors, that I joined the Thogus Products family as a process technician. I immediately started to realize just how many different plastics there were, and how much processing variation could exist in a facility that ran so many custom jobs.

Over the course of the next six years I enrolled in three additional technical training programs and gained a great deal of invaluable experience. My experience expanded across many different machines, several types of robots and automation, and of course multiple types and grades of plastic. Fast forward to March 2015, I was then offered an opportunity to be among the inaugural class of the AIM Institute in Erie Pennsylvania - an opportunity I will be eternally thankful for and know I will benefit from for the balance of my career. 

Upon taking the entrance test for the AIM Institute (strictly for the sake of gauging current level of knowledge) I realized two things. First, this was not going to be a walk in the park. Second, I simply did not know nearly as much as I thought I did in the realm of injection molding. I was a fair mixture of nervous and excited. But, since I only had a week’s notice before the first of the four classes I was not able to do any research on what exactly I had signed up for; and therefore possibly less nervous than I would have been. Previously, I had read many articles both written by and written about John Beaumont, Mike Sepe and John Bozzelli and recognized them as leaders and pioneers in their respective corners of the plastics world. Little did I know that they would be among the instructors that would be teaching the AIM institute classes. I was a bit star-struck to say the least when I first entered the classroom and saw their name tags on the desks. I remember thinking “I might be out of my league here.” Turns out the mix of students in that class ranged from product design, to tooling, to processing and even quality control. The class, thankfully, is designed to work for anyone in the plastics world.

Throughout the next year I learned plastics - starting at the molecular level and working all the way through tool design, processing and even part review and design. The classes, while very challenging (even for the Thogus, degreed plastics engineer who was taking the class as well), were not the usual “take your information and go” type of classes. There was an enormous amount of support not only during the class and on the homework assigned between classes, but on any day of the week at any time. The instructors were just an email away and their responses were always prompt and informative. They want the students to succeed and their passion for the plastics industry was always evident. I admittedly had rough patches in some areas, but I was never completely lost. When I needed help it was always available.

In addition to the support from the instructors at the AIM Institute, the time allotted to me by my workplace to complete the WebEx classes and homework assignments was pivotal in my completion of the certification as well. Without Thogus’ support and encouragement throughout the program I may not have done as well or even have been able to complete and pass the classes. Their investment in me made an enormous difference in my ability to do well and directly impacted how much I was able to digest and retain the information. 

After my grade for the final test came in and I received my certificate in the “Plastics Engineering and Technology” program I had a great sense of pride. I finished the class tied for the top grade, and while the class was not very large, I felt very accomplished. More importantly, I had a measurable increase in confidence. I was able to step up at work and take on a new role with new responsibilities. I bring a new understanding of troubleshooting to every situation and find myself narrowing in on a particular problem so that I can quickly investigate solutions. I am able to look at new designs and recognize potential issues before products are launched, which can make a world of difference once the steel is cut and processing begins. The lessons and education I was afforded by this program have made a world of difference for me in my day-to-day work. Learning real world applications from experts in a professional setting and having the homework and reinforcement between classes made the information stick. It was an experience I will never forget, and the confidence to challenge the industry standards, ask questions and strive to solve problems will be a staple in my career. 

AIM Certificate

 

A Journey of Continuous Improvement

by bree palacios9. December 2014 11:15

 

Continuous improvement is a journey, not a destination. Thogus Products began its adventure in 2009.

Over the course of the past 5 years, Thogus Products has made numerous ‘lean’ changes within the plant floor and offices which have positively impacted the company. ‘Lean’ is a method that many manufacturing companies practice to eliminate overall waste and improve processes. This is accomplished in means of reducing time, product and cost.

One of the most important ways in which Thogus Products creates solutions to eliminate waste is provided through the voice of the employee. Employees are encouraged to submit management alert cards when they find possible solutions to current waste in and around the plant floor. These cards are then reviewed through the Continuous Improvement Department where a new process is established and employees are then trained appropriately.

During the beginning of their ‘lean’ journey, Thogus Products invested in robotic arms to separate parts from the tooling cavities. Conveyors allowed parts to cool before dropping into a box to be sorted.

Listed below are further ways in which Thogus has created new ‘lean’ processes:

- AC and a chiller system were installed within the past two years which helped control the environment and the rate at how quickly parts cooled.

- Gaylord tippers were suggested by employees to allow material to continuously flow into the press hoppers. Portable gaylord tippers are also used which allow operators to tip/lift material from any location within the plant. This, too, was a suggestion by an employee.

- Job boards can be seen located at each press which display work order information, instructions, change process, lights, outlets and room to work freely. These boards allow operators to find all information needed to have a successful production run. The boards are also portable, which allows the operators to take them to other stations if needed.

- A forklift charging station was recently created in November. This station appears as a mini parking lot. All forklifts are to be returned to the station when not being used. There, other employees can locate the lifts and will have no worries of them not being charged.

There is no such thing as perfect, but Thogus Products believes that there is always room for improvement.

Portable gaylord tipper- Suggestion by Employee  

Portable gaylord tipper

 

 

 

 

 

 

 

 

 

 

Portable Job Boards- Suggestion by Employee

                  

 

 

 

 

 

 

 

 

 

 

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